Protective device for ventilating-fans.



No. 831,284. IA'JI'EII'IED SEPT. 18, 1906.

R. A. ILG. I PROTECTIVE DEVICE FOR VENTILATING FANS.

APILIOATIOH- FILED FEB. 3, 1905.

W] T NESSES I 27 "UNIT D STATES PATENT OFFICE.

ROBERT A. ILG, OF CHICAGO, ILLINOIS, ASSIGNOR OF ONE-HALF TO THERESA ILG, OF CHICAGO, ILLINOIS.

PROTECTIVE DEVICE FOR VENTlLATlNG-FANS.

Specification of Letters Patent.

Application filed February 3, 1905. Serial No. 244,028.

To all whom it may concern:

Be it known that I, ROBERT A. ILG, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Protective Devices for Ventilating-Fans, of which the following is a specification.

My invention relates to ventilating-fans of that type known as direct-driven fans, wherein the electric or other motor is a plied directly to the shaft of the fan. Sue fans are commonly located in openings in walls and serve the function of driving ofi the more or less foul or tainted air in the room to which they are applied. Where such fans are driven by electric motors a plied directl to the fan-shaft, the current 0 air drawn 0 by the'fan necessarily passes over and in contact with the frame and windin s of the motor, and where this air is more orfess charged with corrosive fumes and gases the latter exert an injurious effect upon the parts of the motor.

A leading object of my invention, therefore, is to provide a protective device for fanmotors, especially such as are employed in ventilating rooms or chambers wherein the air is necessarily impure, such as chemical and other laboratories, paint-shops, kitchens, foundries and machine-shops, and the like.

It is also a well-known fact that electric motors after they have been started in operation gradually lose a small percentage of their efliciency by reason of the heat devel oped in the windin s and other parts of the motor. Where sue a motor is mounted directly on a fan shaft, this evil is of course somewhat mitigated, owing to the presence of the air-current, which is constantly flowing over and around the same, and the device of my present invention embodies as an important feature thereof means whereby such a cooling action of the motor is not only preserved but enhanced coexistently with the protective feature.

My invention in a preferred mechanical form is illustrated in the accompanying drawings, wherein-- Figure 1 is a central vertical section through a ventilating-fan equipped with my improvement. Fig. 2 is a side elevational view of the protective device detached, and

Patented Sept. 18, 1906. 1

may be assumed to represent the interior of a kitchen, laboratory, or other chamber to be ventilated, the space to the left of the wall representing the outer atmosphere or any ot er space into which the fan discharges.

8 designates the fan of the usual form and type, which is mounted on a suitably-journaled fan-shaft 9, dis osed centrally of the casing 7. On the she 9 is directly mounted an electric motor, conventionall illustrated at 10, said motor being sup orte in an annulus 11, carried by a series 0 bracket-arms 12 suitably fastened to the fan-casing 7 or to the wall 5 adjacent to the same.

Referring now to those parts wherein my invention resides, 13 desi nates a cylinder of sufiicient size to surroun the motor 10 with a considerable annular space therebetween, one end of said cylinder bein closed by a removable cover or cylinderead 14, which may be secured thereto by bayonet-joints 15 or 111 any other suitable or convement manner, the cyhnder and its cover themselves forming a device in the nature of a protective hood for the motor. The opposite end of the cylindrical portion of the hood has a series of outwardlyent apertured ears or lugs 16,

whereby the hood may be rigidly secured, as

by bolts or rivets 17, to the supporting-arms 12. Preferably, also, to the same end of the hood is secured an annular extension 18 in the form of a frustum of a cone, said extension being conveniently secured in place at the same time that the hood is applied to the motor by extending .bolts or rivets 17 through ears or lugs 19, projecting radially of the member. Tapping the cylinder 13 near its outer end is an elbow-shaped pipe 20, the other end of which extends throug the wall 5, preferably just below the casing-opening 6. The inlet end of said pipe is preferably provided with a guard in the nature of a strainer 21 to prevent the inflow of impurities from the outside.

The hood covering the motor is made of sheet metal, the outer surface of which is enameled, which renders the hood proof against the deleterious effect of many corrosive gases.

When the fan is set in operation by the motor, the current of air drawn therethrou h, as indicated by the arrows, passes over the cod, but entirely out of contact with the motor and its immediate supporting parts, whereby the latter are fully protected, the hood by its presence offering but a slight and practically negligible obstruction to the flow of the aircurrent. At the same time the fan sets up a v strong suction-current through the lateral 1nphere is coo v The screen'2l in the inflowforced, the location let-pipe 20 of the hood, which current 1mpinges directly upon the motor and coming as it usually does from the outside atmosand effects. a much reater cooling of the motor than has hereto ore been effected byits bath in the current of air underoing, expulsion from the room or chamber eing ventilated. I have found in practice that the cooling effect upon the motor thus obtained enhances the efliciency of the motor to a de ee considerably in excess of the slight redi ction of the ventilating effect upon the room produced by the presence of the hood. i

.' Where the air, vapors, or gases discharged by the fan are lighter than the air outside the room or chamber, as is usually the case,

Whe-elbow-pipe 20 is located on the under side .of; the fan, as shown, so as i-flow of the same through to avoid the backthe elbow-pipe. .Where, however, such air, fumes, or gasesexelled by the fan are of greater specific grav ity than the atmosphere into which they are of the inlet-pipe 20 will be reversed, so as to lie above the fan, for the reasons already stated.

' The inner extension member 18 of the hood, while rendering the protection afforded by the latter more complete, is not essential to its effectiveness for 1ts intended purpose. ipe 20 may also be employed or omitted, as esired.

The hood may of course be made with its cylindrical portion 13 and end portion 14 integral, although I prefer to make the latter separable, as shown, since in that case the motor can be inspected, set u andremoved Without disturbing the cylindrical portion of the hood and its inflow-pipe.

While I have shown and described a practicable and desirable mechanical embodiment of my invention, yet it is to be understood that the invention is by no means limited to the particularform and construction of a paratus hereinabove set forth, but may e varied in respect to details within the general purview and principle thereof.

I claim 1. The combination with an electric'motor and a ventilating-fan mounted directly on the armature-shaft thereof, of a protective .hood of less diameter than and wholly in rear of said fan surroundingl said motor with its open end adjacent'to t e suction side of the fan, said fan being uncovered on its suction side whereby the current induced by the fan flows over said hood, and a suction-pipe leading from a point exterior to the room or chamber containin the motor and tapping said hood, substantially as described.

2. The combination with an electric motor and a ventilating-fan mounted directly on the armature-shaft thereof, of a protective hood of less diameter than and wholly in rear of said fan surround' said motor with its open end adjacent td tlie suction side of the fan, said fan being uncovered on its suction side whereby the current induced by the fan flows over said hood, and a suction-pipe lead ng from a point exterior to the room or chammotor and tapping said her containing the substantially as hood laterally'ofthe motor,

described. 4

3. The combination with an annular fancasing ada ted to be located in an opening in the wall 0 a room or chamber, of an electric motor supported b and concentrically with said fan-casing an having a ventilating-fan mounted directly on the armature-she. thereof, a protective hood of less diameter than and wholly in rear of said fancovering the sides and inner end of said motor with its open end adjacent to the suction side of the fan, the space between the open end of said hood and said fan-casing being open whereby the currentinduced by the fan flows over said hood, and a suction-pipe leading) from a point exterior to the room or cham er containing the motor and tapping said hood, substantially as described.

4. The combination with a ventilating-fan and a motor mounted on the shaft thereof, of a protective device for said motor comprising a cylindrical member surrounding the motor, a removable cap or cover OlOSIDgthG end of said cylindrical member remote from the fan, and an annular member convergent toward the fan applied to said cylindrical member, scribed. I

5. The combination with a ventilating-fan and a motor mounted on the shaft thereof, of a protective the opposite en substantially as dey dof' 6. The combination with an electric motor from a. point exterior to the room or chamber 10 and e ventilating-fan mounted directly on containing the motor and tapping said hood; the armature-shaft thereof, of a rotective and a strainer in said suction-pipe, substanhFod elf ess diameteg than acllld who ly in 1fear tially as described.

0 sai an surroun in sai motor wit its open end adjacent to t e suction side of the ROBERT fan, seid fan being uncovered on its suction Witnesses:

side whereby the current induced by the fan SAMUEL N. Pom),

flows over said hood, a suction-pipe leading FREDERICK C. Goonwm. 

